Land use around protected areas affects functional diversity, but not species richness in anuran assemblages

Human-made habitat modifications drive biodiversity loss, especially through land use changes. These modifications impact the structure and diversity of local assemblages, primarily through habitat loss and fragmentation. They can also affect adjacent areas, including protected ones, resulting in connectivity loss between neighboring sites. Our study evaluated how land use influences species richness and functional diversity in amphibian assemblages. Data were collected over 12 monthly expeditions from January 2013 to December 2014. We sampled 81 ponds across eight protected areas and their surroundings in Paraná and Santa Catarina, measuring species abundance and 21 ecomorphological traits. We performed phylogenetic eigenvector regression to control phylogenetic autocorrelation in species traits. We estimated functional diversity as the total branch length of functional dendrograms for species in each assemblage. We use structural equation modelling to estimate the effects of spatial, landscape, land-use and microhabitat variables on species richness, abundance and functional diversity based on a hypothetical causal model. Land use influenced only functional diversity, whereas species richness was primarily shaped by spatial factors and pond structural characteristics. These distinct drivers emphasize the importance of measuring multiple dimensions of diversity to develop effective conservation strategies.